[Effect of dose fractionation on the carcinogenicity of chemical substances]

Abstract

Interrelations between single and total doses of chemical carcinogens are considered. On the basis of the data published and the author's own works a conclusion is drawn on the single dose as a decisive factor determining the organotropism (cytotropism) of certain pluripotential carcinogens (DMNA, DENA, DMH). Fractionation of the dose enhances the effect of polycyclic aromatic hydrocarbons, probably decreases the effect of directly acting carcinogens. Tumours of different histogenesis may respond to the dose fractionation in a different way.